The aim of the study is to obtain information on cerebral glucose metabolism measured with the 18F-FDG PET technique in normal subjects without current or previous neurological or psychiatric pathologies in order to use the data obtained for voxel-based statistical analyzes for comparison with individual subjects ( patients with disease neurological or psychiatric) which will be evaluated with the same method to improve the specificity and diagnostic sensitivity of the FDG PET exam.

The objective is to obtain a functional measure of brain glucose metabolism in every normal subject because this is a functional measure of brain activity. The subjects will represent different decades of age to have a wider range of comparison with patients.

Inclusion Criteria:

• absence of neurological and psychiatric pathologies, negative pregnancy test.

40 healthy volunteers, over 40 years of age, capable of understanding and wanting, who have not had a previous clinical history of neurological or psychiatric diseases, will be enrolled. Subjects with cognitive impairment and who at the time of recruitment are taking drugs active on the central nervous system will be excluded.